terrorism (n)
the use of violence and threats to intimidate or coerce, especially for political purposes.
this definition has been helpful for me in getting back to the roots of the word and the concept. i used to think that the word 'terrorist' meant someone who would kill or harm un-armed civilians to make a statement - you know, like flying planes into buildings and stuff.
yet many of my friends are "terrorists" for blocking the doors to banks or disrupting the logging plans of one company or another (and even the state of oregon). none of them did anything to intimidate anyone, yet they bear a government-assigned title which renders them as enemies of society.

the fbi defines terror like this: “the unlawful use of force or violence against persons or property to intimidate or coerce a government, the civilian population, or any segment thereof, in furtherance of political or social objectives.” (source)

force against property for social objectives? this means you never have to become violent or even threaten violence to be a terrorist in the u.s. 
the department of homeland security, which lists the protection of u.s. economic interests as a major component of its mission, sicked thirty riot cops on us for standing in front of the bank with signs (may 1, 2012 in eugene). this dhs group is operated out a fusion center known as the oregon terrorism information threat assessment network, which  focuses on the "sharing of threat-related information between the federal government and state, local, tribal, territorial (sltt) and private sector partners."
private sector partners. the department of homeland security answered directly to the bank we were protesting!

when i protest, i put myself directly in the way of fully-armed and potentially violent men and women with the power to charge me with any crime they so desire. my experience protest, on the whole, has been self-sacrificial where it could have been intimidating, positive and kind where it could have been negative and vicious. 

for me, one model protestor is martin luther king jr., who spoke out against an unjust war and domestic systems of racism and classism at great personal cost. another is jesus, who stood up against a still-iconic empire and made the mold for non-violent resistance. jesus emphasized the greatest way to love was to "lay down your life for your friends." hardly a terrorist.
the first time i saw a police officer point a gun at me, i had feelings of sheer horror that reached down to my toes. i saw officers strike un-armed women with their clubs and the feelings of fear reached their height. for effective terrorism, you can't beat the u.s. government. as my friends always say, 'the state has a corner on violence.'

will potter writes a catchy little ditty about the canadian government's efforts to re-brand long-standing domestic environmental groups as "terrorists".